Zimmerman has said he shot the 17-year-old in self-defense, though Martin was reportedly carrying only a bag of Skittles and an iced tea when he was killed. Despite a loud national outcry, Zimmerman has not been arrested or charged in Martin’s death.

According to Tampa Bay Fox affiliate WTVT-TV, what the witness says he saw could bolster Zimmerman’s claim that he shot Martin in self-defense:

“The guy on the bottom who had a red sweater on was yelling to me: ‘help, help…and I told him to stop and I was calling 911,” he said.

Trayvon Martin was in a hoodie; Zimmerman was in red.

The witness only wanted to be identified as “John,” and didn’t not want to be shown on camera.

His statements to police were instrumental, because police backed up Zimmerman’s claims, saying those screams on the 911 call are those of Zimmerman.

“When I got upstairs and looked down, the guy who was on top beating up the other guy, was the one laying in the grass, and I believe he was dead at that point,” John said.

Watch below:

On Friday night, Zimmerman attorney Craig Sonner appeared on CNN’s “Anderson Cooper 360″ and said he client sustained a broken nose and a head laceration on the night of the incident.

“His nose was broken, he sustained injury to his nose and on the back of his head he sustained a cut that was serious enough that probably should have had stitches…it was an injury that was done by Trayvon Martin,” Sonner said.